Prostatic ultrasonography and biochemical analyses of expressed prostatic secretions will be carried out in addition to the usual diagnostic studies (including serum acid phosphatase and prostatic specific antigen) on patients evaluated for symptoms of bladder outlet obstruction or for assessment of palpable prostatic abnormalities detected on rectal examination. Following biopsy, simple prostatectomy or radical prostatectomy, the removed tissue will be studied both histologically and biochemically. Whole mount preparations will be performed on the radical prostatectomy specimens to determine the extent and volume of tumor and the presence or absence of capsular or seminal vesicle invasion. Receiver Operating Characteristics (ROC) analysis will be performed to assess the ability of digital rectal examination and transrectal ultrasonography (linear array and radical scanning with different transducers) to detect abnormalities, specifically carcinoma and extent of invasion. The ultrasound findings will be compared with the physical examination, the histological findings and the biochemical studies to determine if these tests used either alone or in combination have a role in the early detection and staging of prostatic carcinoma.